I've read a book once in which an old man was teaching a young boy how to grow tomatoes. He was listening to radio music and told the boy that music is needed for the tomatoes to grow healthy. It was funny, as a story it was fine.
However, i don't think how music or talking to plants can help growth. I have a lot of flowers in my apartment and I'm checking them every day, sometimes I say something to them, just for fun but I don't think it has an effect on them.
Caring on the other hand, has effect on flowers or plants. To get results you need to learn as much as possible and give your plants and flowers the best care you can. Outside gardening unfortunately is not what it was once, climate change is affecting us all, especially the plants.
We used to have four seasons and that was normal. Now we have three. Sometimes there is no Spring, other times there is no Autumn. We have snow in April and there's beach weather in November. This can confuse your plants an cause damages. Lack of rain require watering,
Watering now is a priority, you can't do without that. Using natural and organic fertilizer can help you get a better result. using plant rotation is a must, change the place where you plant your plants every year, never use the same place for the same plant twice in a row. This way the soil can rest and you can avoid infection spreading.
And if you think you can help growth with music, you can do it, it won't harm the plants :)